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Game for anything

By Gail Vines

Animal Play edited by Marc Bekoff and John Byers, Cambridge University Press,
£19.95/&dollar;32.95, ISBN 0521586569

THIRTY years ago an engineering student at the University of Texas climbed
the Austin campus tower with a rifle. He killed 17 people and wounded 31 before
the police gunned him down. What compelled this young man with a “Mr Clean”
public image to become a mass murderer? Psychiatrist Stuart Brown, one of the
contributors to Animal Play, led the task force set up to find the
answer. Signs of a brain tumour or serious drug addiction were expected, Brown
remembers. Yet in the end the experts blamed an abusive father and a childhood
devoid of play.

Brown went on to study dozens of young murderers, only to find that “normal
play behaviour was virtually absent throughout their lives”. He now believes
that play enables children to develop empathy, social altruism and the means to
handle stress, humiliation and powerlessness, and that play-starved children
become adults at risk of social and personal breakdown.

But why exactly is play so good for us? Insights into the wellsprings of
emotional health may come from a better understanding of how and why play has
evolved in the animal kingdom, argue Marc Bekoff and John Byers, the editors of
this wide-ranging collection of recent research from North America, Australia
and Britain. Until recently, few researchers saw play as a topic suitable for
serious scientific investigation. As a result, no one knows whether most mammals
play, let alone whether other vertebrates do, and much remains to be
discovered.

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The urge to play could be surprisingly ancient. Pigface, a 50-year-old Nile
soft-shelled turtle, long captive at the National Zoo in Washington DC, has
learnt to ease the boredom of life in a tank by nosing, biting, chewing, shaking
and swimming through a round hoop of garden hose. His behaviour is an example of
“object play”, argues herpetologist Gordon Burghardt of the University of
Tennessee at Knoxville. Among birds, play is unambiguously indulged in by
parrots and members of the crow family. Ravens, in particular, are known for
their antics and acrobatics—even repeatedly sliding down snow-covered
roofs on their backs “for the fun of it”, says Bernd Heinrich of the University
of Vermont at Burlington.

But might playfulness accord benefits other than sheer pleasure? Animal
Play highlights an intriguing variety of possible explanations. Because
animals playing with their peers have to negotiate these cooperative ventures,
they could be learning how to make sense of the intentions of others, argues
Bekoff of the University of Colorado at Boulder. He points to distinctive
postures—notably canine “play bows”—which domestic dogs, coyotes and
wolves use to signal that what follows is intended as playful.

Theorists have long supposed that play sharpens competitive prowess, but a
blow-by-blow analysis of hamsters and rats at play suggests that their behaviour
is a poor means of practising fighting, says Sergio Pellis of the University of
Lethbridge in Alberta, Canada. He suspects, however, that play might help
overcome a fear of launching attacks. Apparently, adult cats that are bad
mousers can be turned into better predators by injections of anxiety-reducing
benzodiazepines.

Focusing on the timeframe of youthful play in a variety of species, John
Byers of the University of Idaho at Moscow links “locomotor play” to the
development of the brain’s movement-control centre, the cerebellum. The
developmental timing of play in baby mice, cats, antelopes and baboons coincides
with the postnatal window in which specific brain remodelling is under way. Play
among these young animals reaches a peak just as the neural architecture of
their cerebellum is being permanently modified, he says. Thus play could provide
experiential feedback to at least one part of the brain, enabling it to reorder
its synaptic connections in the light of experience. It’s an intriguing idea
that underlines just how much the still youthful study of play has to teach us.